Hi Everyone, co-creator of Nova here.
The inspiration for Nova came when I was in sales at CloudFlare. There we saw the benefit of personalizing emails, but it was so time consuming and didn't scale.
We previously shared a version of Nova built around Campaigns, we’re excited to release Nova Inbox, which brings the personalization quality right to the inbox experience, via a snazzy sidebar.
Please check it out, would love to hear your feedback!

@louis_sugar A variety of public sources and no, all you need is the business email address in your CRM (though a full name helps with coverage). There's a lot involved in collecting and cleaning the data to obtain high coverage with high accuracy. And then there's a lot of other proprietary datasets and algorithms that go into it... You'll see once you try it that there's a bit of complexity there. Our next release (next week) will go quite a bit further still. Thanks for the question.